Income taxes	3 Months Ended
Mar. 31, 2018
Income taxes
Income taxes	9. Income taxes Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax basis of assets and liabilities using statutory rates. A valuation allowance is recorded against deferred tax assets if it is more likely than not that some or all of the deferred tax assets will not be realized. Due to the uncertainty surrounding the realization of the favorable tax attributes in future tax returns, the Company has recorded a full valuation allowance against the Company’s otherwise recognizable net deferred tax assets. For the three months ended March 31, 2018, the Company recognized a de minimis tax expense in other comprehensive income related to the unrealized gain on available-for-sale securities. For the three months ended March 31, 2017, the Company recognized a tax expense in other comprehensive income of $0.2 million related to the unrealized gain on available-for-sale securities.

Income taxes

3 Months Ended

Mar. 31, 2018

9. Income taxes

Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax basis of assets and liabilities using statutory rates. A valuation allowance is recorded against deferred tax assets if it is more likely than not that some or all of the deferred tax assets will not be realized. Due to the uncertainty surrounding the realization of the favorable tax attributes in future tax returns, the Company has recorded a full valuation allowance against the Company’s otherwise recognizable net deferred tax assets.

For the three months ended March 31, 2018, the Company recognized a de minimis tax expense in other comprehensive income related to the unrealized gain on available-for-sale securities. For the three months ended March 31, 2017, the Company recognized a tax expense in other comprehensive income of $0.2 million related to the unrealized gain on available-for-sale securities.